There are four main phases of the monthly periods.
Monthly periods begins on the first day of menstruation, when blood starts to come out of the vagina.
Menses is the 1st phase of monthly periods. After then, comes follicular, ovulatory and luteal phase.
Follicular phase starts with menstrual bleeding and typically lasts 13 to 14 days.
During the beginning of the follicular phase, women experience low levels of
female hormones like estrogen and progesterone.
The ovulatory phase starts with a flowing of Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH) levels. LH stimulates egg release (ovulation), which usually occurs 16 to 32 hours after the
flowing begins. In this phase, level of LH that causes the bone loss, depression or
mood swings decreases during its flow and the level of hormone like FSH that
controls menses and pregnancy starts to increase.
During the luteal phase, female hormone levels decreases. After releasing the
egg, it breaks through the surface of the ovary. The yellow hormone secretes in
the body in the female reproductive system formed in an ovary so the process of
fertilization begins. In this stage, hormone like progesterone also produces to
control the condition of the inner lining of the uterus. The hormones which are
important for sexual and reproductive development is high in this phase.
Figure: Graph representing the natural variability in the menstrual hormones during the monthly periods